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Biomedical subjects

F U Niethard

Publications and source records attributed to F U Niethard.

At least 19 recordsLinked to original sources
PubMed1999

The risk of paraplegia through medical treatment.

In the Orthopedic University Hospital of Heidelberg (section Orthopedics II, treatment and rehabilitation of paraplegics), 21 patients with iatrogenic paraplegia were treated between 1968 and 1991. Paraplegia occurred in nine cases after procedures close to the spinal cord. In 12 cases paraplegia complicated medical treatment. Procedures close to the spinal cord, such as laminectomy, vertebrotomy, spondylodesis, and peridural anaesthesia, involve the risk of mechanical damage to the spinal cord, the level of paraplegia depends on the area of treatment. Any previous damage to the spinal cord increases the risk of paraplegic complications. The main risks in procedures distant from the spinal cord, such as vascular surgery, angiography, radiotherapy, bronchial artery embolisation, and umbilical artery injection, are disturbances of the blood supply or toxic mechanisms. The ischaemic genesis of spinal cord damage is obvious in the case of vessel ligatures or cross-clamping of the aorta with resulting hypotonic discirculation. In radiomyelopathy as well, the damage to the spinal vessels outweighs the direct neuronal damage. Corresponding to the vascular cause, lesions are more likely to occur at the level of borderlines of blood supply in the middle thoracic cord or in the area of a non-anastomosed great radicular artery in the lumbar spinal cord. Knowledge of the consequences and side effects of medical treatment is imperative. Knowing about the risk of a paraplegic lesion, we need a strict indication for diagnostic and therapeutic interventions. Due to progress in science some of the reasons of iatrogenic paraplegia have become manageable. Especially in radiotherapy, vascular surgery and angiography the risk of neurological complications has been lowered.

Adolescent↗
PubMed1998

Glucocorticoids regulate the expression of the human osteoblastic endothelin A receptor gene.

The endothelial cell-derived peptide endothelin 1 (ET1) stimulates cell proliferation and differentiated functions of human osteoblastic cells (HOC), and HOC constitutively express the endothelin A receptor (ETRA). Therefore, ET1 may play an important role in the regulation of bone cell metabolism. As glucocorticoids (GC) exert a profound influence on bone metabolism and increase the effects of ET1 on bone cell metabolism in vitro, the effects of GC on ETRA expression in HOC were investigated. Dexamethasone (DEX) increased ETRA mRNA levels in a dose- and time-dependent fashion. The effects of dexamethasone, prednisolone, and deflazacort on the increase of ETRA mRNA levels correlate positively with their binding affinity to the GC receptor. Scatchard analysis of ET1 binding data to HOC revealed that DEX increased the binding capacity for ET1 from 25,300 to 62,800 binding sites per osteoblastic cell, leading to an enhanced mitogenic effect of ET1 on HOC after preincubation with DEX. Transiently transfected primary HOC with a reporter gene construct, containing the 5'-flanking region of the ETRA gene fused to luciferase gene, showed a promoter-dependent expression of the reporter gene and the induction of reporter gene expression by DEX treatment. Total RNA extracts of femoral head biopsies with osteonecrotic lesions from GC-treated patients showed threefold higher ETRA mRNA levels compared with extracts of bone biopsies from patients with traumatically induced osteonecrosis and coxarthrosis. Furthermore, GC treatment increased plasma ET1 levels by 50% compared with pretreatment values. These findings suggest that GC induced upregulation of ETRA, and ET1 plasma levels enhance ET1's anabolic action on bone cell metabolism. Increased ET1 concentrations may also impair bone perfusion by vasoconstriction in a metabolically activated skeletal region.

Adult↗
PubMed1998

Increased urinary crosslink levels in aseptic loosening of total hip arthroplasty.

The diagnosis of aseptic loosening in total hip arthroplasty is predominantly based on clinical and radiographic evaluation. Loosening is usually associated with increased bone resorption at the interface. In this study we wanted to evaluate the diagnostic value of bone markers in aseptic loosening. We compared 50 patients with proven component loosening during surgery with 50 age-, sex-, and implant-matched patients without clinical or radiological signs of loosening. We measured serum markers of bone formation (bone-specific alkaline phosphatase, osteocalcin [OC], procollagen type I propeptides) and bone resorption (collagen n-telopeptide [NTX], deoxypyridinoline [DPYD], pyridinoline [PYD]). We found significantly increased levels of NTX, DPYD, PYD, and OC in the loosening group. The other markers showed no significant difference between both groups. We conclude that determination of urinary crosslinks may offer a new and valuable diagnostic method in the detection of aseptic loosening in total hip arthroplasty.

Adult↗
PubMed1998

Thanatophoric dysplasia type II: new entity?

There is some question about whether the two forms of thanatophoric dysplasia (TD), Type II with and Type I without cloverleaf skull, belong to the same entity. Thus, we investigated one 6-day-old TD with cloverleaf skull using examination of the external phenotype, radiology, autopsy, skeleton preparation, large section histology, detailed section histology, and ultrastructure. The loss of the three-phase contours-characteristics for Type I (54)--in certain metaphyses, the absence of the perichondral spurs to some extent, and their substitution by a structure similar to the perichondral "ring of Lacroix" have a suggested origin in normal cartilage-bone tissue. The same mechanism is postulated (a) for the appearance of less bent or normally shaped tubular bones compared with TD Type I, and their corresponding increased mechanical stability, and (b) for the less amount of platyspondyly in Type II than in Type I. We suggest that the malformation of the cloverleaf skull has its origin in the promontory growth of the relatively normal cartilage-bone tissues at the skull base resulting in an early synostosis and a consecutive fusion of the cranial sutures. The ultrastructural analysis of chondrocytes demonstrates the significant contribution of electron microscopy for TD studies. We suggest that pathologically altered light chondrocytes accounts for plump cross-striated collagen fibrils, the reduced cellular proliferation, and the impaired formation of columnar and hypertrophic zones. It is clear that normal cartilage-bone tissue distributed among "thanatophoric" tissue is the reason for the differences between Type I and Type II. Hypotheses are presented that explain this tissue mosaicism. Thus, TD Type I and TD Type II do not represent two different entities but the same entity with varying features due to mutational events occurring at different times.

Bone and Bones↗
PubMed1998

The different appearance of the oculodentodigital dysplasia syndrome.

We report on two families with the oculodentodigital (ODD) dysplasia syndrome, also called Meyer-Schwickerath syndrome. It represents a rare disorder characterized by eye and facial abnormalities causing a unique facial appearance. The phenotype of the young patients resembles those of identical twins. We found syndactyly mostly at the hands and, additionally, characteristic phalangeal aberrations, defects in teeth enamel, and trichosis. In the one family, the ODD dysplasia syndrome seemingly originated in a new mutation. The affected child was treated surgically in our clinic (syndactyly separation). In the other family, three patients (grandmother, mother, and granddaughter) were subjects of syndactyly separation. The aim of our surgeries was to separate the webbed fingers so there would be a normal spread and to improve the function and appearance of fingers. The ODD dysplasia syndrome correlates with the Hallermann-Streiff syndrome, or oculomandibulodyscephaly, which is characterized by a typical skull shape (brachicephaly with frontal brossing), a bird-like face, and eye abnormalities (congenital cataracts and microphthalmia).

Abnormalities, Multiple↗
PubMed1998

Thanatophoric dysplasia type I: new radiologic, morphologic, and histologic aspects toward the exact definition of the disorder.

A comprehensive seven-step study on THANATOPHORIC DYSPLASIA without cloverleaf skull (TD Type I) was carried out postmortem on three aborted fetuses of 19, 26-27, and 34 weeks and one preterm neonate of 35 weeks gestation, respectively. The characteristic x-ray configuration of the spine in TD Type I presenting with H-, U- or reversed U-shape vertebrae were shown to correlate with the inclination or reclination of the vertebral bodies within a kyphotic or lordotic segment. The bowing of the tubular bones in TD Type I is explained by a diminished mechanical stability that is causally related to a specific cartilage structure. The perichondral spurs are defined by their morphologic structure, and their origin is attributed to a normal perichondral ossification in the presence of an impaired enchondral ossification. Impairment of enchondral ossification was more evident in the periphery than in the center of the metaphyses leading to a tongue-shaped osseous cone directed toward the epiphysis. The perichondral spurs and the linguiform enchondral growth plate resulted in a three-phase maple leaf-like contour of the metaphyses of tubular bones and acetabular roof. The nature of the perichondral fibrous bands, the fibrovascular bundles, and the fibrovascular bands of the growth plate and their significance in atypical ossification processes are discussed in detail. It is suggested that the diminished longitudinal growth of the skeleton is caused by a reduced mitotic activity of cartilage cells in the proliferative zone leading to a reduction of cell numbers in the columnar zone transversely oriented spongiosa bars resulting from desmal ossification of the metaphyseal fibrovascular structures.

Bone and Bones↗
PubMed1997

Scoliosis and congenital anomalies associated with Klippel-Feil syndrome types I-III.

STUDY DESIGN: This investigation was aimed at characterizing anomalies and syndromes associated with Klippel-Feil syndrome in a large group of patients. The authors evaluated the clinical and radiographic features, documented the associated anomalies, and registered the type of treatment. OBJECTIVE: The anomalies or syndromes and the development of scoliosis were correlated to the type of Klippel-Feil syndrome. MATERIAL AND METHODS: In a cross-sectional study, the authors reviewed data from 57 patients with Klippel-Feil syndrome treated over 25 years at the Department for Orthopedics of the University of Heidelberg. The patients (17 males and 40 females; average age of the first contact, 12 years) were classified into three types according to the description of Feil in 1919. RESULTS: Klippel-Feil syndrome Type I (fusion of cervical and upper thoracic vertebra with synostosis) and Type II (isolated cervical spine) corresponded to 40% and 47% of patients, respectively. Type III (cervical vertebra associated with lower thoracic or upper lumbar fusion) was displayed in 13% of the patients only. The authors found a variety of combinations of Klippel-Feil syndrome and other anomalies in the patients examined in this study, with 67% of the patients characterized by an association with other disorders or syndromes. Of the patients, 70% showed scoliosis. Its degree depended on the type of Klippel-Feil syndrome. Scoliosis in Type I correlated with 31 degrees (Cobb angle), in Type III with 23 degrees, and in Type II with 9 degrees only. Thus, Type II, with isolated cervical fusion, shows a low risk for scoliosis. CONCLUSION: This study increases knowledge of a wide range of anomalies and syndromes identified in association with Klippel-Feil syndrome. A special finding of the study was a correlation between the degree of scoliosis and Klippel-Feil syndrome Types I, II, and III.

Abnormalities, Multiple↗
PubMed1997

Influence of isokinetic and ergometric exercises on oxygen partial pressure measurement in the human knee joint.

We conducted the first in vivo investigation on the influence of joint movement on intraarticular oxygen partial pressure. The development of a special flexible microcatheter allowed measurements of intraarticular oxygen partial pressure under both physiological and pathological conditions. The aim of this study was to evaluate the influence of different knee joint stresses on intraarticular oxygen partial pressure under physiological (healthy patients) and pathological (patients with osteoarthritis) conditions. The results show that the different exercise patterns influence the intraarticular oxygen partial pressure. Patients with osteoarthritis showed a lower increase of intraarticular oxygen partial pressure compared with healthy patients. This phenomenon is directly correlated to the degree velocity of the isokinetic exercises. We found the same results under ergometric conditions. This method allows functional, intraarticular in vivo measurements under different exercise patterns. For the first time, we were able to measure the influence of joint movement on the intraarticular process of nutrition under physiological and pathological conditions. Also, to evaluate for the first time in vivo different concepts for osteoarthritis therapy.

Adult↗
PubMed1997

Endothelin-1 is a potent regulator of human bone cell metabolism in vitro.

Endothelial cell products may affect bone cell function, since trabecular and cortical bone are in close proximity to vascular endothelial cells. Incubation of cultured human osteoblastic cells with the endothelial cell polypeptide endothelin-1 (ET-1) resulted in a time- and dose-dependent stimulation of cell proliferation. Furthermore, markers of differentiated osteoblastic function, i.e., alkaline phosphatase and type-I collagen, were dose-dependently increased in response to ET-1. The effects of ET-1 on cell growth and function reached a maximum at higher ET-1 concentrations, and osteoblastic cells bound ET-1 specifically with a KD of 35 pM, corresponding to the biologic effects of ET-1 on bone cells. Under baseline conditions osteoblastic cells expressed 16,800 binding sites per cell. The effect of ET-1 was dependent on its binding to the endothelin-1 receptor A (ETRA), since an inhibitor of ET-1 binding blocked the biologic effects of ET-1. Northern blot analyses revealed that cultured human osteoblastic cells possess the transcript for the ETRA. Expression of ETRA mRNA was under control of 1,25-dihydroxyvitamin D3 [1,25 (OH)2D3]. Incubation of osteoblastic cells with 1,25(OH)2D3 increased ETRA mRNA levels, corresponding to an increased effect of ET-1 on osteoblastic proliferation and function. Thus, a concerted action of the endothelial cell polypeptide ET-1 and 1,25(OH)2D3 may mediate an osteoanabolic effect of the vascular and endocrine vitamin D system.

Adult↗
PubMed1997

Principles of treatment of the upper extremity in arthrogryposis multiplex congenita type I.

The involvement of the upper limb in arthrogryposis multiplex congenita for many patients means a far-reaching dependency on outside help. The extension contracture of the elbow joint especially makes it impossible to reach the mouth or to perform hygienic necessities. Therefore, the rehabilitation program includes an improvement of passive elbow flexion by capsulotomy or of active flexion by triceps transfer if possible, or both. In bilateral involvement, the optimal solution is to have one arm in flexion for reaching the head and mouth passively or even actively and one arm in extension for hygienic necessities. From 1973 to 1993 we performed 22 releases of the elbow contracture in 16 children. An additional triceps transfer was performed in five elbows. The overall results showed a marked increase of the range of motion and a functional improvement concerning the daily activities (in 17 children). In 5 children there was no gain but also no loss of functional capacities. In 3 of 5 children with an additional triceps transfer, an improvement of active flexion was attained. Pre- and postoperative physiotherapy is at least as important as the operative procedure itself.

Adolescent↗
PubMed1997

[Etiology and pathogenesis of spondylolytic spondylolisthesis].

The commonly accepted hypothesis set up by Brocher in 1950 that the dysplasia of the pars interarticularis vertebrae is an essential requirement for the occurrence of spondylolysis should be thought over in light of recent findings. Newly published investigations show that disturbed spinal growth leads to dysplasia of the vertebral arch and to spondylolysis. Disturbances that play an important role are biomechanical stress factors that result from the evolution from a quadripedal to a bipedal human locomotion as well as stress fractures of the vertebral pars inter-articularis and defects in vertebral maturation in small infants.

Adult↗
PubMed1996

Development of pathological lumbar kyphosis in myelomeningocele.

We analysed the cases of lumbar kyphosis in 151 (21%) of a series of 719 patients with myelomeningocele. Three different types were distinguished: paralytic, sharp-angled and congenital. In a cross-sectional and partly longitudinal study the size and magnitude of the kyphosis, the apex of the curve and the level of paralysis of each group were recorded and statistically analysed. Paralytic kyphosis (less than 90 degrees at birth) occurred in 44.4% and increased linearly during further development. Sharp-angled kyphosis (90 degrees or more at birth) was present in 38.4% and also showed a linear progression. In both types, progression seemed to depend also on the level of paralysis. Congenital kyphosis occurred in 13.9% and we could find no significant factor which correlated with progression.

Cross-Sectional Studies↗
PubMed1996

Juvenile progressive scoliosis and congenital horizontal gaze palsy.

Eleven articles reporting 39 patients with the combination of progressive scoliosis and familial congenital gaze palsy have now been published. This disorder appears to be caused by a malfunction of the normal equilibrial control mechanism related to the brainstem or the central nervous system. The scoliosis progresses when the children begin to walk. Even when they are treated with physiotherapy or brace, they often require early operation. We consider that progressive juvenile or infant scoliosis associated with familiar congenital horizontal gaze palsy constitutes a clinical entity. We report two sisters with congenital gaze palsy, in one of whom scoliosis of at least 70 degrees (Cobb) developed, and review and analyze all cases published until now.

Child, Preschool↗
PubMed1994

[Three-dimensional ultrasound image of the infant hip].

Ultrasound imaging of the infant hip has gained wide acceptance, especially in diagnosis and therapy of infant hip dysplasias. Problems are the prognosis with regard to normal and pathological alpha-angle and treatment using cast, harness, or pillow. The well-known two-dimensional ultrasound techniques are not able to reproduce the correct relationship between femoral head and acetabulum. The use of the new three-dimensional technique is independent of the position of the infant hip. Although a special view into the acetabulum is possible, at present this method is not suitable for screening programs.

Acetabulum↗
PubMed1993

The Haglund imprint on the patella.

Seven hundred and five radiographs of the knee were examined and 17.6% showed a so-called Haglund imprint on the patella. The incidence was the same in patients with chondromalacia and in a control group. There was no statistical difference regarding age, sex and body weight. Haglund's imprint is a variation from the normal and is of no diagnostic value.

Body Weight↗
PubMed1993

The ultrastructure of articular cartilage of the chicken's knee joint.

The articular cartilage and synovial membrane of immature and mature chicken knee joints were studied by light, scanning and transmission microscopy. The findings differed from human articular cartilage and we conclude that the chicken knee joint is not suitable as a model for human joint degeneration.

Animals↗
PubMed1993

[The current status of prenatal diagnosis of myelomeningocele--results of a questionnaire].

Questionnaires were sent to 1000 parents of children with myelomeningocele in order to get a better knowledge of the present state of prenatal diagnosis of this disease. 566 parents answered; 488 responders, in whom the pregnancy took place 1982 and later, were evaluated in detail. 85% of the parents reported having been checked by ultrasound 2 times and more during pregnancy: however, only 27% of the myelomeningoceles were detected before delivery. 83% were diagnosed between the 30th and 40th week of pregnancy. The rate of discovery rose from 0% and 37% between 1982 and 1990. As a consequence of this result, one should make every effort by using ultrasound and alpha-foetoprotein-screening to verify or to exclude a myelomeningocele in an early phase of pregnancy. The delivery should take place in a specialised centre, and the knowledge of life expectancy and life quality of these patients should be improved, for the obstetricians as well as for the parents.

Child, Preschool↗